Variable Number Tandem Repeats in the Mitochondrial DNA of Lentinula edodes

Variable number tandem repeats (VNTRs) in mitochondrial DNA (mtDNA) of Lentinula edodes are of interest for their role in mtDNA variation and their application as genetic marker. Sequence analysis of three L. edodes mtDNAs revealed the presence of VNTRs of two categories. Type I VNTRs consist of two types of repeat units in a symmetric distribution, whereas Type II VNTRs contain tandemly arrayed repeats of 7- or 17-bp DNA sequences. The number of repeat units was variable depending on the mtDNA of different strains. Using the variations in VNTRs as a mitochondrial marker and the A mating type as a nuclear type marker, we demonstrated that one of the two nuclei in the donor dikaryon preferentially enters into the monokaryotic cytoplasm to establish a new dikaryon which still retains the mitochondria of the monokaryon in the individual mating. Interestingly, we found 6 VNTRs with newly added repeat units from the 22 mates, indicating that elongation of VNTRs occurs during replication of mtDNA. This, together with comparative analysis of the repeating pattern, enables us to propose a mechanistic model that explains the elongation of Type I VNTRs through reciprocal incorporation of basic repeat units, 5’-TCCCTTTAGGG-3’ and its complementary sequence (5’-CCCTAAAGGGA-3’).

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Mitochondrial DNA variable number tandem repeats (VNTRs): utility and problems in molecular ecology

Molecular Ecology ◽

10.1046/j.1365-294x.1998.00495.x ◽

1998 ◽

Vol 7 (11) ◽

pp. 1441-1455 ◽

Cited By ~ 151

Author(s):

DAVID H. LUNT ◽

LAWRENCE E. WHIPPLE ◽

BRADLEY C. HYMAN

Keyword(s):

Mitochondrial Dna ◽

Tandem Repeats ◽

Molecular Ecology ◽

Variable Number ◽

Variable Number Tandem Repeats

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Variable number tandem repeats in the mitochondrial DNA Control region of the Chinese alligator, Alligator sinensis

Amphibia-Reptilia ◽

10.1163/156853806776052038 ◽

2006 ◽

Vol 27 (1) ◽

pp. 93-101 ◽

Cited By ~ 1

Author(s):

Shengguo Fang ◽

Qianghua Xu

Keyword(s):

Mitochondrial Dna ◽

Control Region ◽

Tandem Repeats ◽

Repetitive Sequences ◽

Variable Number ◽

Alligator Mississippiensis ◽

Chinese Alligator ◽

Evolutionary Features ◽

Alligator Sinensis ◽

Variable Number Tandem Repeats

AbstractVariable number tandem repeats (VNTRs) are present in the control region of mitochondrial DNA (mtDNA) of the alligatorid species; however, the evolutionary dynamics of the repetitive sequences and the significance of the VNTRs in the context of genetic monitoring of these species are not well explored. The Chinese alligator, Alligator sinensis is critically endangered and is now largely in captive breeding. Previous studies in mitochondrial genes revealed little genetic diversity existing within the populations. We reported here the structural variation and evolutionary features of mtVNTRs in the Changxing population of the species. The mtVNTRs contained 676∼785 base pairs, made up by 5 distinct motifs repeated 31∼36 times in 32 individuals examined. The motifs were 21∼22 nts in length, with high sequence similarity between each other and with those of the American alligator (Alligator mississippiensis), indicating origination of the mtVNTRs from a single ancestral duplication unit in both species. The 5′ and 3′ portions of the repetitive sequences in the Chinese alligator were very much conserved among the individuals, while those in the middle showed a higher degree of sequence variation. The frequency of each motif appearing in the mtVNTRs showed positive correlation to the binding energy of the potential secondary structure the motif could adopt. 17 VNTR types, of which, 6 from the second generation and 12 from the third generation were identified from the samples. Analysis of the multiple VNTR types showed a high level of stochastic mutation within each generation. The suitability of the mtVNTRs as a marker to monitor the genetic differentiation of the Chinese alligator was also discussed.

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Molecular characteristics of Brucella melitensis isolates from humans in Qinghai Province, China

Infectious Diseases of Poverty ◽

10.1186/s40249-021-00829-0 ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Zhi-Jun Zhao ◽

Ji-Quan Li ◽

Li Ma ◽

Hong-Mei Xue ◽

Xu-Xin Yang ◽

...

Keyword(s):

Tandem Repeats ◽

Brucella Melitensis ◽

Draft Genome ◽

Geographic Origin ◽

Variable Number ◽

Human Brucellosis ◽

Molecular Characteristics ◽

Whole Genome ◽

Qinghai Province ◽

Variable Number Tandem Repeats

Abstract Background The prevalence of human brucellosis in Qinghai Province of China has been increasing rapidly, with confirmed cases distributed across 31 counties. However, the epidemiology of brucellosis transmission has not been fully elucidated. To characterize the infecting strains isolated from humans, multiple-locus variable-number tandem repeats analysis (MLVA) and whole-genome single-nucleotide polymorphism (SNP)-based approaches were employed. Methods Strains were isolated from two males blood cultures that were confirmed Brucella melitensis positive following biotyping and MLVA. Genomic DNA was extracted from these two strains, and whole-genome sequencing was performed. Next, SNP-based phylogenetic analysis was performed to compare the two strains to 94 B. melitensis strains (complete genome and draft genome) retrieved from online databases. Results The two Brucella isolates were identified as B. melitensis biovar 3 (QH2019001 and QH2019005) following conventional biotyping and were found to have differences in their variable number tandem repeats (VNTRs) using MLVA-16. Phylogenetic examination assigned the 96 strains to five genotype groups, with QH2019001 and QH2019005 assigned to the same group, but different subgroups. Moreover, the QH2019005 strain was assigned to a new subgenotype, IIj, within genotype II. These findings were then combined to determine the geographic origin of the two Brucella strains. Conclusions Utilizing a whole-genome SNP-based approach enabled differences between the two B. melitensis strains to be more clearly resolved, and facilitated the elucidation of their different evolutionary histories. This approach also revealed that QH2019005 is a member of a new subgenotype (IIj) with an ancient origin in the eastern Mediterranean Sea.

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Slipped-Strand Mispairing at Noncontiguous Repeats in Poecilia reticulata: A Model for Minisatellite Birth

Genetics ◽

10.1093/genetics/155.3.1313 ◽

2000 ◽

Vol 155 (3) ◽

pp. 1313-1320 ◽

Cited By ~ 2

Author(s):

John S Taylor ◽

Felix Breden

Keyword(s):

Tandem Repeat ◽

Poecilia Reticulata ◽

Tandem Repeats ◽

Phylogenetic Reconstruction ◽

Variable Number ◽

Repeat Motif ◽

Raw Material ◽

Direct Repeats ◽

Mt Dna ◽

Variable Number Tandem Repeats

Abstract The standard slipped-strand mispairing (SSM) model for the formation of variable number tandem repeats (VNTRs) proposes that a few tandem repeats, produced by chance mutations, provide the “raw material” for VNTR expansion. However, this model is unlikely to explain the formation of VNTRs with long motifs (e.g., minisatellites), because the likelihood of a tandem repeat forming by chance decreases rapidly as the length of the repeat motif increases. Phylogenetic reconstruction of the birth of a mitochondrial (mt) DNA minisatellite in guppies suggests that VNTRs with long motifs can form as a consequence of SSM at noncontiguous repeats. VNTRs formed in this manner have motifs longer than the noncontiguous repeat originally formed by chance and are flanked by one unit of the original, noncontiguous repeat. SSM at noncontiguous repeats can therefore explain the birth of VNTRs with long motifs and the “imperfect” or “short direct” repeats frequently observed adjacent to both mtDNA and nuclear VNTRs.

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